Existing transport refrigeration systems are used to cool containers, trailers, and other similar transport units (typically referred to as a “refrigerated transport unit”). Modern refrigerated transport units may be efficiently stacked for shipment by ship or rail. Typically, when refrigerated transport units are shipped by tractor, a single refrigerated transport unit is placed on a trailer chassis. When cargo in the container includes perishable products (e.g., food product, flowers, etc.), the temperature of the refrigerated transport unit must be controlled to limit loss of the cargo during shipment.
There are strict governmental regulations covering engine emissions from engines that run at or over 25 horsepower (HP). Some engines that meet these regulations may be too large to fit in a TRS. Engines that run at or under 25 HP have less restrictive regulations and can fit into a TRS. However, in some instances, a TRS may need more than 25 HP power to operate properly.